I've always thought Blyleven should be in. I don't understand why he's penalized for having a long career. The career 3.30 ERA and 1.20 WHIP speak for themselves and have nothing to do with his longevity. Being in the upper echelon of MLB pitchers for the better part of 22 years should enhance his status, not diminish it.
His W/L percentage, as is the case with all pitchers not named 1972 Steve Carlton, is mostly a function of the teams he played for. In '74, for example, he won 17 with a 2.66 ERA, 249 SO and 19 CG (none of which were career bests, by the way). Those ERA, W and SO totals are pretty comparable to what Santana's done the last couple of years. Why does it matter that he also lost 17 that year? How much better could he have pitched?
Also, I think the 3,700 SO and 242 CGs are monster numbers that simply should not be ignored whether compiled over 22 years or 30 years.